Flanges, joints, and various pressure lines and pressure vessels are widely used in the industry. Opposed flanges on separate members are formed with aligned openings and the two members are joined to one another in a pressure type manner by first providing a gasket between the two flanges and then by connecting the flanges together with threaded stud-like members, such as studs, bolts, or stud-bolts, which extend through the aligned openings and have a nut engaged thereon. The amount of torque applied to the nuts normally determines the tensioning of the studs. It is important, particularly in large diameter members, that the tension in the studs be sufficient to withstand imposed forces and be uniform as to avoid deformation of the flanges and the members to which they are fixed. The term "stud" as used herein refers to stud-like members to which the invention applies.
Various devices have been provided heretofore for tensioning studs and have been hydraulically actuated as well as non-hydraulically actuated. The nuts are normally rotated by a driving member fitting over the nuts for rotating the nuts in a manner sufficient to obtain the desired tensioning of the stud on which the nut is positioned.
Prior art stud tensioning devices have utilized a gear fitting over a nut in driving relation with the gear rotated by a power mechanism engaging the gear for rotating the gear and the nut. The nut is threaded onto a stud for tensioning the stud. A power device, such as a fluid motor or reciprocating cylinder, has been removably connected to the drive mechanism for effecting rotation of the gear and the associated nut.
In subsea operations the flange members are connected to each other in subsea completion systems, such as completion systems for subsea gas wells, and it is desirable that stud tensioning devices be operated from remotely operated vehicles (ROV), particularly at increased water depths. Many of the subsea oil and gas wells are positioned at water depths over 2,000 feet which is generally undesirable for divers. The torque applying device must be capable of fitting over a nut and powered from a suitable fluid motor for rotation to obtain the desired tensioning of the stud.
In some subsea uses, the torque device is utilized for applying a torque to a shaft for rotating or driving a separate member. For example, an adapter having a male hexagonal end may be inserted within the gear opening with the adapter receiving a shaft on an opposite end for rotating the shaft. The shaft may be connected to a valve for actuating the valve, for example.
It is an object of the present invention to provide a device for tensioning studs which is easily positioned about a nut on the stud for rotation of the nut to a desired tensioning of the stud.
Another object of the invention is to provide such a tensioning device which is particularly adapted for subsea use and operation from a remotely operated vehicle (ROV).